Whitepaper: Quantitation of LONG®R3 IGF-I

This entry was posted on May 11, 2016 by admin.

Quantitation of LONG®R3 IGF-I during production and purification of recombinant proteins from cell culture

Thomas H. Ermak, Ph.D. and Amanda Flies, Ph.D.

This paper discusses the use of a recently developed ELISA kit to measure the IGF1 analog LONG®R3 IGF-I in mammalian cell culture media during the production of recombinant proteins. The structures of LONG®R3 IGF-I, Native IGF1 and Insulin are compared, and an immunoassay for the quantitation of LONG®R3 IGF-I is described.

Abstract
LONG®R3 IGF-I is an analog of human insulin-like growth factor 1 that has been bioengineered for use in cell culture during production of recombinant proteins in human cells. LONG®R3 IGF-I comprises the 70 amino acids of IGF-1 with an arginine substitution for glutamic acid at amino acid 3 and a 13 amino acid extension peptide at the N-terminal end for a total of 83 amino acids. LONG®R3 IGF-I has a lower affinity for IGF binding proteins increasing its bioavailability to the IFG-1 receptor present on cells in culture. When supplemented in serum-free medium, it promotes cell proliferation and increases cell survival and productivity through better proliferative and anti-apoptotic signaling. A LONG®R3 IGF-I ELISA kit was recently developed to monitor the levels of LONG®R3 IGF-I in culture medium during the production process. The assay measures concentrations of LONG®R3 IGF-I in the 0.31 to 40 ng/ml range. The ready-to-use ELISA kit facilitates measurement of LONG®R3 IGF-I during optimization of the cell culture process and downstream processing purification.